Small wire fire on firewall
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New Member
Joined: Aug 2022
Posts: 69
From: South Carolina
We never found the smoking gun, the cause for the link to blow. It should, in theory be a short to ground in the tens of amps. I expected us to find it when you rigged up the initial fused connection but the problem did not repeat. Maybe it was the trailer module or a short that was relieved from moving wires around. I thought it was going to be the alternator but it tested ok. Intermittent failure? I wanted to find and correct the cause with you, that’s the right way to go about this but when you first reconnected everything and the fuses didn’t blow that left us with no clues to chase. Can a 16 gauge corroded link blow from the standby current of a truck in the off position? Maybe if the standby current is too high because a an unresolved parasitic draw problem. You don’t have an amp clamp meter to easily chase that. We could go through the parasitic draw process with an in-line a meter to check.
George
George
Correct my thinking here.... if fusible link (B) burned up, then the problem must have been on D (alternator) or (E) that ignition wire.
Or maybe it was B all along. I may open up that fusible link to look at the wire that’s left. It certainly was corroded at the junction block. If the wires were corroded through a significant portion, it could have turned that 16G wire into a 32G wire since the current would have less good copper to travel through.
and I want to say it again. I am so appreciative of your help
BF Veteran
Joined: Jan 2007
Posts: 4,622
From: Florida
Yes corrosion equals increased resistance which equals increased heat for a given amount of current. The parasitic draw of your truck in the off position should be something like a 10th of an amp or less but I don’t know what the temporary spikers when you connect the battery and everything wakes up before it goes back to sleep. Whatever that number is it’s not enough to blow a normal healthy fusible link but like you said if it really was not 16 gauge then that could be it. Yes it was something down the stream of the fusible link so either the alternator, the feed to the fire wall which should be the ignition or the trailer module. It’s my pleasure.
George
George
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New Member
Joined: Aug 2022
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From: South Carolina
i certainly had parasitic draw before the fusible link burned up. Battery wouldn’t last more than a few weeks if I did not start it up.
Correct my thinking here.... if fusible link (B) burned up, then the problem must have been on D (alternator) or (E) that ignition wire.
Or maybe it was B all along. I may open up that fusible link to look at the wire that’s left. It certainly was corroded at the junction block. If the wires were corroded through a significant portion, it could have turned that 16G wire into a 32G wire since the current would have less good copper to travel through.
and I want to say it again. I am so appreciative of your help
Correct my thinking here.... if fusible link (B) burned up, then the problem must have been on D (alternator) or (E) that ignition wire.
Or maybe it was B all along. I may open up that fusible link to look at the wire that’s left. It certainly was corroded at the junction block. If the wires were corroded through a significant portion, it could have turned that 16G wire into a 32G wire since the current would have less good copper to travel through.
and I want to say it again. I am so appreciative of your help
BF Veteran
Joined: Jan 2007
Posts: 4,622
From: Florida
George
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New Member
Joined: Aug 2022
Posts: 69
From: South Carolina
But the battery cables had been disconnected all night. And I only just reconnected the positive cable. The negative was only “connected” once I put the multimeter in line to test. So I did not see if that allowed the dome light to come on.
I will redo. But I may have a problem with the multimeter sitting still for 15 minutes as I don’t have an actual post on the negative to clamp to, but one of those screw ins. I’ll try to jury rig up something.
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New Member
Joined: Aug 2022
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From: South Carolina
so I closed the door and held the multimeter (on the 10A port) in line and it fluctuates between 0.00 and 0.01 amps (0 and 10 mA). So I felt it was safe to move the red lead back to the normal port (max 200mA). I switched to 200mA on the dial and it fluctuates between 03.7 and 03.8. I switched it to 20mA on the dial and I got 3.74mA. I held it for about 4 minutes until my knees and back ached. And it never changed. That doesn’t seem like a lot of parasitic draw.
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New Member
Joined: Aug 2022
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From: South Carolina
so at this point, you would just make it permanent and monitor the situation?